Drownproofing is a method for surviving in water disaster scenarios without sinking or drowning. It is also famous as a class once required at the Georgia Institute of Technology.
Drownproofing is a method for surviving in water disaster scenarios without sinking or drowning. It is also famous as a class once required at the Georgia Institute of Technology.
Drownproofing was developed by swimming coach Fred Lanoue, known to students as Crankshaft because of his limping gait. It was first taught in 1940. [1] His method was so successful that it gained national recognition, and Georgia Tech soon made it a requirement for graduation, until 1988. [2] The US Navy also took interest, and adopted it as part of their standard training. [3] It is claimed that during Lanoue's time teaching at Tech from 1936 to 1964, he taught drownproofing to some 20,000 students. [4]
Once they had mastered the Drownproofing technique, students learned to stay afloat with their wrists and ankles bound, swim 50 yards (46 m) underwater, and retrieve diving rings from the bottom of the pool using their teeth. Lanoue published a book called Drownproofing, a New Technique for Water Safety in 1963. [5] Georgia Tech dropped the course from its curriculum in 1988, as part of a downsizing of its physical education and athletics department. [6]
Drownproofing has been for many years widely taught to recruits in the U.S. Navy, U.S. Marine Corps, and U.S. Coast Guard.
Reagh "Doc" Wetmore, swimming coach at Boston University, shared Fred Lanoue's enthusiasm for Drownproofing and continued to teach the technique until his retirement at the end of 2005. [7]
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In Drownproofing terminology, the great majority of people are "floaters". That is to say that, with the lungs fully inflated (or say at total lung capacity), they have slightly less specific gravity than water and will not start to sink until they exhale. [8] An average floater has 3–4 lb (1.4–1.8 kg) of positive buoyancy in fresh water. "Sinkers" can also benefit from a modified technique, but will find it more difficult to learn and will probably need specialised coaching.
In the Drownproofing survival technique, the subject floats in a relaxed, near-vertical posture, with the top of the head just above the surface. Using the arms or legs to exert a downward pressure, the subject raises himself sufficiently so that the mouth is above the surface and a breath is taken, before dropping back into the relaxed float. This is done several times a minute (typically between 5 and 10), depending upon the needs of the individual. It is important to keep the lungs fully inflated for the maximum possible time and to exhale and inhale rapidly when a breath is taken. The technique is easy to learn and does not require arduous training or a high standard of physical fitness. With practice, it is possible to remain afloat in this way for a long time with minimal effort. Lanoue taught his students to perform the technique with hands and feet tied, thus demonstrating that it is possible to survive even when injured or otherwise disabled.
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The main criticism of Drownproofing is that, with the body almost totally immersed, heat loss will be greater than with vigorous swimming or treading water, with the consequent earlier onset of hypothermia. [9] [ citation needed ] But other sources suggest that heat loss is increased by vigorous action, because it displaces relatively warmer water that is trapped by the subject's clothing.[ citation needed ] [10] In any cold water situation, the main objective should be to get out of the water and find shelter and dry clothing. In any case, Drownproofing should never be regarded as a substitute for the normal safety precautions recommended for any water activity.[ citation needed ]
The effects of heat loss can be reduced by using the Heat Escape Lessening Posture (H.E.L.P). The Heat Escape Lessening Posture was designed for use with a Personal Flotation Device. Essentially the person grabs their knees to reduce the surface area exposed to the water and centralize body heat. It can be adapted and used as part of the drownproofing technique but is far more challenging due to the physical exertion required to hold your body in this shape, and the near impossibility of keeping your legs pressed to your torso while your hands are bound behind your back.[ why? ]
Swimming is the self-propulsion of a person through water, or other liquid, usually for recreation, sport, exercise, or survival. Locomotion is achieved through coordinated movement of the limbs and the body to achieve hydrodynamic thrust that results in directional motion. Humans can hold their breath underwater and undertake rudimentary locomotive swimming within weeks of birth, as a survival response. Swimming requires stamina, skills, and proper technique.
Snorkeling is the practice of swimming face down on or through a body of water while breathing the ambient air through a shaped tube called a snorkel, usually with swimming goggles or a diving mask, and swimfins. In cooler waters, a wetsuit may also be worn. The snorkel may be an independent item or integrated with the mask. The use of this equipment allows the snorkeler to observe the underwater environment for extended periods with relatively little effort, and to breathe while face-down at the surface.
Hypothermia is defined as a body core temperature below 35.0 °C (95.0 °F) in humans. Symptoms depend on the temperature. In mild hypothermia, there is shivering and mental confusion. In moderate hypothermia, shivering stops and confusion increases. In severe hypothermia, there may be hallucinations and paradoxical undressing, in which a person removes their clothing, as well as an increased risk of the heart stopping.
Buoyancy, or upthrust, is a gravitational force, a net upward force exerted by a fluid that opposes the weight of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus, the pressure at the bottom of a column of fluid is greater than at the top of the column. Similarly, the pressure at the bottom of an object submerged in a fluid is greater than at the top of the object. The pressure difference results in a net upward force on the object. The magnitude of the force is proportional to the pressure difference, and is equivalent to the weight of the fluid that would otherwise occupy the submerged volume of the object, i.e. the displaced fluid.
A dry suit or drysuit provides the wearer with environmental protection by way of thermal insulation and exclusion of water, and is worn by divers, boaters, water sports enthusiasts, and others who work or play in or near cold or contaminated water. A dry suit normally protects the whole body except the head, hands, and possibly the feet. In hazmat configurations, however, all of these are covered as well.
A diving suit is a garment or device designed to protect a diver from the underwater environment. A diving suit may also incorporate a breathing gas supply, but in most cases the term applies only to the environmental protective covering worn by the diver. The breathing gas supply is usually referred to separately. There is no generic term for the combination of suit and breathing apparatus alone. It is generally referred to as diving equipment or dive gear along with any other equipment necessary for the dive.
Human swimming typically consists of repeating a specific body motion or swimming stroke to propel the body forward. There are many kinds of strokes, each defining a different swimming style or crawl.
A buoyancy compensator (BC), also called a buoyancy control device (BCD), stabilizer, stabilisor, stab jacket, wing or adjustable buoyancy life jacket (ABLJ), depending on design, is a type of diving equipment which is worn by divers to establish neutral buoyancy underwater and positive buoyancy at the surface, when needed.
A surface marker buoy, SMB, dive float or simply a blob is a buoy used by scuba divers, at the end of a line from the diver, intended to indicate the diver's position to people at the surface while the diver is underwater. Two kinds are used; one (SMB) is towed for the whole dive, and indicates the position of the dive group throughout the dive, and the other, a delayed surface marker buoy, DSMB or decompression buoy, is deployed towards the end of the dive as a signal to the surface that the divers have started to ascend, and where they are going to surface. Both types can also function as a depth reference for controlling speed of ascent and accurately maintaining depth at decompression stops. Surface marker buoys are also used by freedivers in open water, to indicate the approximate position of the diver when submerged. They may also be used to support a catch bag or fish stringer by underwater hunters and collectors. A DSMB is considered by recreational scuba divers and service providers to be a highly important item of safety equipment, yet its use is not part of the entry level recreational diver training for all training agencies, and there are significant hazards associated with incompetent use.
Diving physics, or the physics of underwater diving is the basic aspects of physics which describe the effects of the underwater environment on the underwater diver and their equipment, and the effects of blending, compressing, and storing breathing gas mixtures, and supplying them for use at ambient pressure. These effects are mostly consequences of immersion in water, the hydrostatic pressure of depth and the effects of pressure and temperature on breathing gases. An understanding of the physics behind is useful when considering the physiological effects of diving, breathing gas planning and management, diver buoyancy control and trim, and the hazards and risks of diving.
A diving weighting system is ballast weight added to a diver or diving equipment to counteract excess buoyancy. They may be used by divers or on equipment such as diving bells, submersibles or camera housings.
Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface breathing gas supply, and therefore has a limited but variable endurance. The name scuba is an anacronym for "Self-Contained Underwater Breathing Apparatus" and was coined by Christian J. Lambertsen in a patent submitted in 1952. Scuba divers carry their own source of breathing gas, usually compressed air, affording them greater independence and movement than surface-supplied divers, and more time underwater than free divers. Although the use of compressed air is common, a gas blend with a higher oxygen content, known as enriched air or nitrox, has become popular due to the reduced nitrogen intake during long or repetitive dives. Also, breathing gas diluted with helium may be used to reduce the effects of nitrogen narcosis during deeper dives.
A personal flotation device is a flotation device in the form of a vest or suit that is worn by a user to prevent the wearer from drowning in a body of water. The device will keep the wearer afloat with their head and mouth above the surface – they do not have to swim or tread water in order to stay afloat and can even be unconscious.
The Davis Submerged Escape Apparatus, was an early type of oxygen rebreather invented in 1910 by Sir Robert Davis, head of Siebe Gorman and Co. Ltd., inspired by the earlier Fleuss system, and adopted by the Royal Navy after further development by Davis in 1927. While intended primarily as an emergency escape apparatus for submarine crews, it was soon also used for diving, being a handy shallow water diving apparatus with a thirty-minute endurance, and as an industrial breathing set.
Numerous Georgia Tech legends and traditions have been established since the school's opening in 1888, some of which have persisted for decades. Over time, the school has grown from a trade school into a large research university, and the traditions reflect that heritage. One of the cherished holdovers from Tech's early years, a steam whistle blows every weekday at various times to mark the changing of classes. It's for this reason that the faculty newspaper is named The Whistle.
Certain species of fish and birds are able to locomote in both air and water, two fluid media with very different properties. A fluid is a particular phase of matter that deforms under shear stresses and includes any type of liquid or gas. Because fluids are easily deformable and move in response to applied forces, efficiently locomoting in a fluid medium presents unique challenges. Specific morphological characteristics are therefore required in animal species that primarily depend on fluidic locomotion. Because the properties of air and water are so different, swimming and flying have very disparate morphological requirements. As a result, despite the large diversity of animals that are capable of flight or swimming, only a limited number of these species have mastered the ability to both fly and swim. These species demonstrate distinct morphological and behavioral tradeoffs associated with transitioning from air to water and water to air.
An emergency ascent is an ascent to the surface by a diver in an emergency. More specifically, it refers to any of several procedures for reaching the surface in the event of an out-of-gas emergency, generally while scuba diving.
The trim of a diver is the orientation of the body in the water, determined by posture and the distribution of weight and volume along the body and equipment, as well as by any other forces acting on the diver. Both static trim and its stability affect the convenience and safety of the diver while under water and at the surface. Midwater trim is usually considered at approximately neutral buoyancy for a swimming scuba diver, and neutral buoyancy is necessary for efficient maneuvering at constant depth, but surface trim may be at significant positive buoyancy to keep the head above water.
Scuba skills are skills required to dive safely using self-contained underwater breathing apparatus, known as a scuba set. Most of these skills are relevant to both open-circuit scuba and rebreather scuba, and many also apply to surface-supplied diving. Some scuba skills, which are critical to divers' safety, may require more practice than standard recreational training provides to achieve reliable competence.
Diving hazards are the agents or situations that pose a threat to the underwater diver or their equipment. Divers operate in an environment for which the human body is not well suited. They face special physical and health risks when they go underwater or use high pressure breathing gas. The consequences of diving incidents range from merely annoying to rapidly fatal, and the result often depends on the equipment, skill, response and fitness of the diver and diving team. The classes of hazards include the aquatic environment, the use of breathing equipment in an underwater environment, exposure to a pressurised environment and pressure changes, particularly pressure changes during descent and ascent, and breathing gases at high ambient pressure. Diving equipment other than breathing apparatus is usually reliable, but has been known to fail, and loss of buoyancy control or thermal protection can be a major burden which may lead to more serious problems. There are also hazards of the specific diving environment, and hazards related to access to and egress from the water, which vary from place to place, and may also vary with time. Hazards inherent in the diver include pre-existing physiological and psychological conditions and the personal behaviour and competence of the individual. For those pursuing other activities while diving, there are additional hazards of task loading, of the dive task and of special equipment associated with the task.